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20 Cards in this Set
- Front
- Back
Thyroid has 2 lobes. What structure unite them?
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the isthmus.
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where is isthmus located?
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-anterior of trachea.
-2nd and 3rd level of tracheal cartilages. -lies deep in the sternohyoid and sternothyroid muscles. |
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Pyramidal lobe present in almost 40% of population.
what are the characteristics of pyramidal lobe? |
-ascend from isthmus (usually left) towards the hyoid bone.
-may be attached to hyoid bone by a fibrous band or muscular slip called: levator glandulae thyroidae |
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what are the coverings of the thyroid gland?
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-surrounded by thin fibrous tissue.
-external to that, a false capsule formed by a sheath of pretracheal fascia; derived of deep cervical fascia. |
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where does the false capsule of thyroid gland attached to?
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-arch of cricoid cartilage
-oblique line of thyroid cartilage. -so it moves along during swallowing and speaking. |
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what are the thyroid gland arterial blood supply and their origin?
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-superior thyroid artery. (from external carotid a)
-inferior thyroid artery. (from thyrocervical trunk) anastomose with each other, but little anastomosis across the median plane. |
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where do the thyroid arteries lie?
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in between the capsule and pretracheal fascia.
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tell the route of thyroid arteries.
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-sup thy a: descend to the superior pole of the gland. run close to ext laryngeal nerve.
-inf thy a: runs superomedially to the carotid sheath > reach post aspect of gland > supply inf pole. closely related to the recurrent laryngeal nerve. |
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what is thyrois ima artery?
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-small, unpaired artery.
-usually arise of the (any): >brachiocephalic trunk >aorta >right common carotid >right subclavian >internal thoracic a -ascend on anterior surface of trachea. -supply isthmus. |
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what are the venous drainage of thyroid gland?
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superior pole: sup thyroid v
lateral parts: mid thyroid v inferior pole: inf thyroid v |
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where do the thyroid veins empty into?
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superior thyroid vein & middle thyroid vein: IJV
inferior tyroid vein: brachiocephalic vein |
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what are the lymphatic drainage of the thyroid gland?
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-pretracheal lymph nodes.
-paratracheal lymph nodes. -deep cervical nodes. |
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what are the nerve supply for thyroid gland?
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postganglionics.
affect gland indirectly thru action on blood vessels. sympathetic: sup,mid,inf cervical sympathetic ganglia. parasympathetic: cardiac and laryngeal branch of vagus nerve. |
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what is the structural unit of the thyroid gland?
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-thyroid follicle.
-spherical cyst-like compartment, various diameter. |
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what is the composition of the folllicular epithelium?
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-a simple squamous,
-simple cuboidal, or -low columnar epithelium. |
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what does the gland's lumen contain?
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pink-staining gel-like mass: called colloid (glycoprotein complex)
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what are the interfollicular connective tissue.
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-extensive network of capillaries.
-fibroblast. -lymphocytes. |
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what are the thyroid gland follicular epithelium?
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2 types:
-principal cell -parafollicular cell |
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what are the characteristics of the thyroid gland's principal cell?
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-shape and size depend on functional state of the gland.
-squamous: inactive -low columnar: active -slightly basophilic cytop. -spherical nuclei (1/more) -function:produce thyroid hormone |
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what are the characteristics of the parafollicular cell of thyroid gland?
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-in periphery of principal cell
-within basal lamina -pale staining -larger than principal cell -solitary/ small clusters. -function: secrete calcitonin |